Genome analysis of alkaliphilic Bacillus halodurans and its perspective to industrial application.
Hideto Takami
Japan Marine Science and Technology Center
An alkaliphilic bacterium, Bacillus halodurans C-125 (JCM9153) was as a B galactosidase and xylanase producer (1, 2). It is the most thoroughly characterized strain, physiologically, biochemically, and genetically, among those in our collection of alkaliphilic Bacillus isolates (3). Analysis of the entire genome of B. subtilis, which is taxonomically related to alkaliphilic B. halodurans strain C-125 except for the alkaliphilic phenotype, has been completed (4). Knowledge of the complete nucleotide sequence of tne B. subtilis genome will definitely facilitate identification of common functions in bacilli and specific functions in alkaliphilic Bacillus strains. We have completed determination of the whole genomic sequence of alkaliphilic B. halodurans C- 125 and its genome was compared with that of B. subtilis (5). The 4,202,353 base-pair genome of the B. halodurans C-125 contains 4,066 predicted protein coding sequences (CDSs), 2141 (52.7%) of which have functional assignments, 1182 (29%) of which are conserved CDSs witn unknown function and 743 (18.3%) of which have no match to any protein database. Among the total CDSs, 8.8% match sequences of proteins found only in B. subtilis and 66.7% are widely conserved in comparison with the proteins of various organisms including B. subtilis. The B. halodurans genome contains IS elements more than 100, indicating that transposases have played an important evolutionary role in horizontal gene transfer and also in internal genetic rearrangement in the genome. Some genes were mutagenized by these IS elements. We attempted to search CDSs whose functions have not been assigned for the signal by using signal peptide prediction program and continuously to search the candidates having signal sequence for motif using PROSITE database to find new extracellular enzymes in the B. halodurans genome. We will present some examples in terms of the CDS assigned functionally by a series of above analysis.
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5. H. Takami, K. Nakasone et al. Nucleic Acids Res. 28 (21) (2000) in press
